compilation - How to compile a .java file in Java?

Question

I have the following code generated by Eclipse (.java file).

import org.eclipse.swt.widgets.Shell;

import org.eclipse.swt.widgets.Display;

public class HelloWorldSWT {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setText("Hello world!");
        shell.open();
        while (!shell.isDisposed()) {
        if (!display.readAndDispatch()) display.sleep();
        }
        display.dispose();
    }

}

Now I want to compile the above file from the command line. I went to the directory where the source code is located and I tried two commands:
1. javac HelloWorldSWT.java
2. javac -d /home/myname/workspace/ HelloWorldSWT.java

In both cases I have the same error "The import org.eclipse cannot be resolved". /home/myname/workspace/ - is the directory where the class file is located.

As far as I understand the compiler does not see the org.eclipse.swt package. Why?

Can it be because the problematic package is located in "/home/myname/workspace/org.eclipse.swt/" (not in "/home/myname/workspace/org/eclipse/swt/")?

Answer 1

You need to set your classpath so that the Java compiler knows where to find the org.eclipse.* classes. You can do that with a command line switch or an environment variable.